Calmore,
I did one of those years ago after the drain pipes outside got bunged up and all the rain watrer came in.
Get someone to help you, its so much easier. I used Chemspecs sanitiser (cant think of its name at the mo) yep it is just spray and wipe down with a cloth, not a sponge, there is no other way really, Calmore its plastic!!!!!!!!!!!!
Take some bin liners along with you to put the clean balls in otherwise they are rolling around all over the place!
And get the local Environmental Health man to come down and check it for you, that way you know it will have been done properly.
You will probably have to do it out of normal hours unless they shut it down for you. Charge normal labour rate plus a bit, when I did ours there was me and 2 girls, took about 3 hours for general work, went back and did the carpet later.
Murky